Compact sphygmomanometer



Feb. 8, 1944. v DAMRQN 2,341,137

COMPACT SPHYGMOMANOMETER Filed Feb. 6, 1943 N TOR.

Arro/e/vsv.

Patented Feb. 8, 1944 UNITED STATE-S PATENT OFFICECOMPAGTISYHYGMOMANOMETER Miit6ii H. fi em n, Camp bo'ckett, em; 7Applet-men February 6, 1943, Serial-No: 4 :5,0'25 461351119.(01128-2455) This invention fiertain's to aruggd; nonbreaka'ble,inexpensive, cor'fibict "sphygmdmas- 'nometer orap'par'atusfordeterminirig' blo'od pressure. It is barticular'ly well-adapted "foruse try the armed forces in the field, "although ififhiay also beemployed to advantage whenever and wherever it is desired to ascertaindiastolic *or systolic bloodpresi'sure. The device iseharacte'r- 'iz'edby its simplicity, freedom from fluids and usefulness. Itis ai-daifitedto perfriit readings'to he made rapidly and the patient may tatke hisotlh blood pressure'tvithout the assistance of others.

The device compr se in effect, auriita-ry'; pres:- =sure applyinguhdindicating meaii's'; the dial of the instrument bing'cali'brtteddirectly in niillimeters of mercury'fdr-systolicpressure as deternzinedby a stethoscopettrid 'r'nrcury rria'hdha- -e er.

' The most common type of sfphygmomanometer employs *a silk 'c'overe'dbanda geflike, 'inflataf ble tube which is wmpeea around the armandinfltte'd by means of a; hand puii'i'p, this inflatable bandage beingesseeiap with a, mercury rhetn or'ne'ter. Itis imposs'ible'to takeerapid reading with this type "or iristrurnerit-"andmettixs must beprovided for supporting the manometer in 'avertical positioii. Asaresult; the' iris trumeht is unsu'ited for use in the [field "orfwi'ththe armed forces and'is 'bul k y, 10'reatkalo'le' and ordinarilyrequires the use of a; stethoscopein order to take readings. I

In comparison, the device of the present'inte'ntion is extremely smalland compact arids'libstahtially unitary, inasmuch as the pressureapplying a'nd mdicating means are an integral part 7 er the device. v 1

Generally stated, theflevic'e comprises a small housing provided with,'a 'wmqdw through which a, calibrated dial is Visible, "the dial being'{cajlibrited in millimeters of mercury. A yieldalzll'e pressure plateforms oh s ide'of the device. 'Ih "use, the pressure plate is applied tothe imi'e'r arrii soa's ttfcdnipre'ssthe brachiai trtery' against thelower fiajrt'of *fihhurnerus', the pr'essurebeing gradua'llly increasediihtiltheplils can notbe-felt.

-'I-he systolic pressure cfifithefibe read directly through'anopefiirig'or wiridow in the case. The 'yieldable pressure of the pressure plate issuppliedhy a; s'pr'ifi so 'thatthe'dei/ice issuhsltar i tially gearless,free from fluids vat-rid praeueeu lion-breakable. I

It is ari obj-eel? of the pre se'r'it invention; there fore,- todisclose and iirdvi'de a 'sfihygniomanometer which-asinex ensive; rugged93nd emeact; j A fur-'tfler elej e'ot o'f the ele ant in've'fitiofi isto :disclo'se andprovide an improved compact-sphygmomanometer which isadapted to pbrm1t readines to be made rapidly;

A still further 'object of the invention/is to diselo'se a'hd provide acompact rsphyg'momandmeter in which the pressure applyingvandr indlcatihg means are substantially integral; the sphygmomanome'ter being freefrom fluids, gearing and other delicate, breakable 'p'i'lts. v

A-still further object 0f the invention ist0'1dis close' a-fid provideacorn-pact, and rugged :sphyg-'- rimihmidmtr ptrtiotflali'ly welladapted fbrw'tlse hyj-thfa-rrhd' forces oh the field of ba'ittle;

These and other objects; use's, aldvantages, adaptations andmodific'ettions wfll b'ecoine apparent-to those skilled iii the aftTrdni tl1'e following deta'ild description er aln i'ierfiplery forminwhich the present inver'itio'n'rr'iety be embodied. In the descriptiongiven hereinafter; reference Will b'lfiad to the appe'fid'd drawing; inwhich:

Fig. '1 shows the device in' use.

Fig; 21'5-8; fro'fit levatiorl.

Fig. 3' is a side elevaitioil. I

Fig. 4 is a side elevation of "the pressure plete 'sideof thede'vice.

Fig. 5 is an emerged transverse seetwn tatkh 'a 'lon the plane 'v' varm.- 2.

Fig. 6 is an enlarged trensversesection through thesteir'r on'ly.

ZBy referring to thedrawirrg it will be noted that the device comprisesa housirig gen'erally indiated at l,--ha-vin"g the sides 2 arid 3; Anopening or window 4 is praviaed iii the housing, said Windowinc'ludirig' a pdifitefer otherindex lrieiilbr 5 to faldilitat accurater'ea diif 0f 534 calibrated dial positiohedwit-hin the hou'siii'g-esdescribed heretfter. Thedevioe' also ifl'llldS a pressure, Dlalte 6which; as b'stillutraltedih Fig. 4 is 'pr'ov'ided With'; c'oricave' edge'1 daffite'd to cooperate with a; ;p'ortioh of the human anatomy andthereby facilitate the afifiliatibfl and use of the device. If desired,asir'ii-iler emacave edge I nij be' formed irith-bb'pbsite margin of thefirs'sufe filait *6. The :presshre plate-Q is yieiddbiy urg aeway fromthe musing I as "by meme of esbire-l wmpmsemnspring-t fis'itifiridbetween the fifes's'lir plltififrd the a hinged or even a ball andsocket connection so as to permit the plate 6 to be tilted somewhat outof a plane perpendicular to the axis of the stem H]. A ball and sockettype of joint is illustrated in detail in Fig. 5, the outer end of thestem It! being provided with a ferrule ll whose fingers grasp aball-ended bolt attached to the pressure plate 6.

The stem Ill extends through a port l2 formed in the side 2 .ofthehousing I. The port lZ-may be formed directly inthe side 2- of thehousing or it may be formed in a removable disc l3 threadedly connectedas indicated at M, to the side 2. The stem l also extends through a portl5 formed in a partition l6 within the housing I, this partition, incooperation with a dome l1 formed in the side 3 of the housing, forminga space within which one end of the stem in may move. The end of stem [0is provided with a head I8 which abuts the partition l6 and limits theoutward movementof the stem l0. underthelinfluence of the spring 8. I

The partition l6 mayhem the form of a thimble whose edge abuts theinnersurface of the side 3, saidthimble being threadedly connected to the.dome l1. Serrationslin the edge of the thimble 16 may then cooperatewith slit ridges in the inner surface of the side -3 so as to preventrotation of the partition thimble It.

Means are provided forpreventing rotation of the stem l0. Such meansmaycomprise a longitudinal or axial groove 20 formed in the outer surfaceof ,thestem l0. and a dog or key cooperating with such groove, the dogor key being a part of or mounted in the disc l3. 7 Rotatably, mountedwithinthe housing I is a rotatable member, such as a disc or wheelZl,provided with an axial opening through which the stem Illzextends. Thehub wheel 2| maybe provided with small, circular outsta-nding beads 22adapted to act as anti-friction means between said wheel, the disc [3,and thepartition IS.

The wheel or disc 2 l, is=preferab1y. provided with indices, which maybe carried by the flange 23, the indices being thus madereadily visiblethrough the opening or window! in the housing I.

Means are provided for translating the axial .movementof the pressureplate 6 and stem in into rotary motion of the disc or wheel 2|. Suchmeans may comprise aspiral groove 24 formed in the stem 10, and asuitable dog or key carried by the wheel 2l and-adapted to extend intothe groove 24. Since the Wheel 2| is restricted from axial movement bythe disc I 3, and the partition 16, axial movement of the stem. ID willbe translated into rotary movement of the-wheel 2|.

A lightbellows made ofsilk, clothor any other suitable material mayextend between the plate Sand the side 2 of the housing I, as indicatedat 21, for the purpose of protecting the spring 8 and the-stem l0 frommoisture, dust and the like. .The bellows 21 is preferably attached '.toboth the plate and the side of the housing.

The spring 8 preferably has a resistance equal to about 250 millimetersof pressure, thereby making certain that the arterial flow of blood willbe stopped when the ,pressure plate 6 is applied to an artery or to theskin immediately above a ,relatively exposed artery onthe body andpressureis applied to the/opposing side 3 of the housing so as to,virtuallycollapse thespring 8.

The calibrations or indices carried by the flange ection molding.

pressure with which the pressure plate is actually pressed against asurface or artery.

The device described hereinabove may be used most successfully in thedetermination of systolic (and diastolic) pressure by causing one of theconcave portions 1 or 1' of the pressure plate to fit above the internalcondyle of the humerus, thereby causing the pressure plate to assume aposition on the internal surface of the human arm above the elbow anddirectly over the bra chial artery. By holding the-instrument againstthe palmar surface of the'fingers of one hand and placing the pressureplate against the inner side of the patients arm in the mannerindicated, the device may be pressed against such inner surface so as tocause the pressure plate 6 to press against the brachial artery to shutoff the flow of blood through said artery. The arterial pulse in thewrist is simultaneously felt by the operator, who observes the movementof the calibrated dial or wheel through the window 4 of the device. Thepressure (as indicated by the calibrated disc or wheel) at which thearterial pulse ceases will be noted and representsthe systolic bloodpressure of the patient.

Preferably this reading is taken rapidly, that is, the pressure of thedevice against the inner arm is raised quickly so as to shut off theflow of blood through the artery, thereby preventing collateralcirculation (through other arteries of the arm) from masking thereadings.

' The diastolic blood pressure may also be obtained by the use of thedevic and by the use the compositions (resinous, phenolic, etc.) havingthe desired strength and rigidity. The plate 6 should be sufficientlystrong to present a smooth, flat, virtually incompressible surfaceduring use. The instrument may be made in large part by It will beunderstood that the present invention is not limited to the use of anyspecific materials or compositions of matternor to the precise size orform of the instrumerit In actual practice,'however, it has been foundthat the entire device need not exceed two inches square in a crosssection transverse to the axis of the stem l0.

7 Those skilled in the art will appreciate that various changes andmodifications may be made without departing from the spirit of theinvention here disclosed. For example,'the rotatable member or wheel- 2|need not carry the flange 23 but instead indices-may be carried alongthe edge, portions of the'wheel 2|, the window 4 bei'ngthen placed inthe side 3 of the device so as to permit readings to be made easily.Moreover, various forms of. thrust bearings may be employed instead oftheanti friction beads 22.

The precise form of device here illustrated is particularly welladaptedfor-use onthe brachial artery against the lower-part of the humerus.

The shape of the pressure plate may be changed, however, in th event-itis desired to use the body, permitting the patient to take his own pulseand simultaneously observe the reading, When an operator is takinganother persons blood pressure with the instrument, it has been founddesirable to place the patients arm across the body of the observer withthe inner side of the arm away from the body of the observer, whereuponthe observer may take the pulse with the fingers of one hand and pressthe device against the brachial artery with the other hand, the patientsarm being thus held between the device and the body of the observer.These are suggestive and illustrative modes of use, other methodsreadily occurring to the operator with changing circumstances.

All modifications and adaptations coming within the scope of theappended claims are embraced thereby.

I claim:

1. A compact and rugged sphygmomanometer comprising: a housing; a portinto one side of the housing; a stem axially movable through said port,said stem being provided with a spiral groove on its surface; arotatable member in the housing, said member being provided with anaxial bore and a dog adapted to engage the spiral groove on the stem;means for restraining said stem from rotation with respect to thehousing; a pressure plate carried by the outer end of said stem; auniversal connection between said pressure plate and stem; spring meansbetween the housing and said plate yieldably urging said plate and stemaway from the housing; a window in said housing adjacent the edgeportion of the rotatable member; and indices carried by the edge portionof the rotatable member and visible through said Window, said indicesdenoting pressure in terms of millimeters of mercury.

2. A sphygmomanometer of the character described in claim 3characterized in that the edge of the pressure plate is provided with aconcavity adapted to cooperate with the internal condyle in facilitatingthe placement of the device with respect to the brachial artery.

3. A compact and rugged sphygmomanometer comprising: a housing; a portin one side of the housing; a stem axially movable through said port;means for restraining said stem from rotation; a pressure plate carriedby the outer end of said stem, said plate being adapted to be placedover an artery; spring means between the housing and said plateyieldably urging said plate and stem away from the housing; a rotatablemember in the housing; means for translating axial movement of the steminto rotation of the rotatable member, said means comprising a spiralgroove formed on the surface of the stem, and a dog carried by therotatable member, said dog being adapted to engage the spiral groove onsaid stem; a window in said housing adjacent the edge portion of therotatable member; and indices carried by the edge portion of therotatable member and visible through said window.

4. A compact and rugged sphygmomanometer comprising: a housing; a portin one side of the housing; a stem axially movable through said port;means for restraining said stem from rotation; a pressure plate carriedby the outer end of said stem, said plate being provided with avirtually fiat face adapted to be placed over an. artery; spring meansbetween the housing and said plate yieldably urging said plate and stemaway from the housing; a member mounted in the housing for rotation in aplane perpendicular to the axis of the stem; means for translating

